In the Department of Otolaryngology at the Johns Hopkins Hospital and the Division of Otolaryngology at the Baltimore City Hospital clinical investigations are carried out on patients with cochlear and vestibular dysfunctions and a variety of pathological conditions involving the different structures of the temporal bone. These investigations include an otolaryngological examination, cochlear and vestibular function studies, roentgenological investigations and, when indicated additional diagnostic studies. The medical, surgical, neurological and neurosurgical examinations are being performed by the respective services. At autopsy the temporal bones, and when indicated, adjacent or important areas of the brain are secured. The temporal bones and sections of the brain are processed in the Temporal Bone Pathology Laboratory in the Traylor Research Building of the Johns Hopkins University School of Medicine. The objectives of this research are to correlate clinical and histopathological observations in an attempt to increase the knowledge about the poorly understood mechanisms of certain disease processes involving the cochlear and vestibular systems and other structures of the human temporal bone.